Traveling type carriage in high speed printers



April 22, 1958 D. N. MacDONALD 2,831,424

TRAVELING TYPE CARRIAGE IN HIGH SPEED PRINTERS Filed March 1, 1954 2 Sheets-Sheet 1 FIG. 3. \32

INVENTOR. DUNCAN N. MacDONALD QM am A T TOR/Vi April 22, 1958- D. N. M DONALD TRAVELING TYPE CARRIAGE IN HIGH SPEED PRINTERS 2 Sheets-Sheet 2 Filed March 1, 1954 l m l h l m w m m l L W mil ATTORNEY TRAVELING TYPE CARRIAGE IN HIGH SPEED PRINTERS Duncan N. MacDonald, Arcadia, Califl, assignor, by

mesne assignments, to Burroughs Corporation, Detroit,

Mich, a corporation of Michigan Application March 1, 1954, Serial No. 413,084

2 Claims. (Cl. 101-93) This invention relates to high speed recording machines and it has particular reference to tabulators for printing numerical information.

Electromechanical tabulators of two general types are commonly employed to record numerical information. In the series type, one character is printed at a time, and the paper is advanced-laterally at the conclusion of each print cycle until. a complete line of characters is printed. This is similar to the common typewriter. in the parallel type, a complete line of characters is printed simultaneously without lateral movement of the paper or carriage. This is similar to the common adding machine.

Tabulators of the series type are of such construction that they are limited to maximum speeds of about ten characters per second. Also, when a group of stored digits are to be printed, special storing circuits are required to feed the information, one digit at a time, to the tabulator. Tabulators of the parallel type can operate at very high speeds, say 600 characters per second, but the mechanism is costly and complex because a print hammer is required for each character position across a page. That is, the number of print hammers required is equal to the number of characters to be printed along each line on the page. Also, complex external storage arrangements are required to provide the required control signals for the numerous print hammers.

The present invention relates to a tabulator which is less complex than conventional high speed tabulators, yet it is capableof printing at speeds up to about 100 characters per second.

The tabulator of my invention is classed as a seriesparallel machine because it prints at block of characters during one print cycle without paper or carriage movement, but it does not print a complete line of copy. The line is completed by conducting several print cycles along the line until the desired number of blocks of characters are printed.

By way of example, a block of ten characters may be recorded during each print cycle and the type carriage may be moved in steps laterally across the paper to permit the desired number of blocks of characters to be recorded along the same line on the paper. After one line is completed, the paper is advanced to the next line, whereupon additional blocks of information are recorded, and so on until the tabulations are completed.

In accordance with a preferred embodiment of my invention, I provide a plurality of type affixed to an endless belt which rotates opposite a plurality of hammers I for actuating the type. The spacing between the print hammers is equal to the spacing between the type on the belt so that any number of the print hammers may be actuated each time that type is located opposite the print hammers. A storage arrangement causes selected print hammers to be operated in synchronism with the movement of the type belt so as to actuate selected type at the desired locations across the page. provided for causing the characters represented by-the type to be printed on paper or other suitable recording media located in the machine.

During each print cycle, this arrangement serves-t0 print a block of characters, with the maximum number of characters in the block being equal to the number of print hammers. Then the type carriage is moved laterally across the paper one step to the location at which the next block of characters is to be printed and the next print cycle is conducted. This procedure'is continued until the entire line is completed, then the paper is moved one step through the machine to the next line, whereupon the next series of print cycles is conducted along the new line.

The number of print hammers is determined by the In the preferred embodiment of the invention, the type I carriage is moved laterally to the locations at which the respective blocks of characters are to be printed along each line. It will be apparent that the paper ma'y'be,

moved laterally in order to accomplish the same result with a fixed type carriage.

The inventionis explained with reference to the drawings, in which:

Fig. 1 is a perspective view of the tabulator of my invention with the top and end coverings removed so as to show the mechanism of the tabulator;

Fig. 2 is a fragmentary view of part of the carriage mechanism showing the type belt and the mechanism which causes it to rotate; I

Fig. 3 shows the entire length of the type belt;

Fig. 4 is a sectional view along line 4-4 of Fig. 1,- showing the carriage mechanism and its relationship to the recording paper;

Fig. 5 is a character position table showing how the respective type move with respect to the print hammers during each print cycle;

Fig. 6 is a schematic diagram showing an electrical control arrangement for the tabulator; and

Fig. 7 shows the arrangement of the commutator segments of the tabulator.

Ten print hammers 11 to 20 are supported on a print hammer carriage 22 (see Figs. 1 and 4). A type carriage 24 supports a type belt 26 opposite the print hammers. A vertical extension 27 on the type carriage pro vides a rigid backing for the type belt. An inked ribbon 28 is located in front of the type belt, and a sheet of paper 30 is supported in the machine so that it is located between the inked ribbon and the print hammers. The tabulations are recorded on the paper 30. vThe type belt is provided with a plurality of raisedtype 32 aflixed to and An inked ribbon is' it is supported by two rotatable spools 34 and 36. The spool 34 is coupled to a splined shaft 38 by a pair of gears 40, 42. The gear 46 is arranged to slide longitudinally along the splined shaft while rotating with it, so that rotation of the splined shaft causes the spool 34 and the type belt to rotate.

The type carriage 24 is supported on the splined shaft 3.8 and an additional shaft 44 so that it is free to move laterally :along the two shafts. Lateral movement of the type carriage is controlled by a carriage position servo motor 46 and a cable 48.. The print hammer carriage 22 is moved in unison with the type carriage by the servomotor 46 and ,a cableSil.

The. print hammer carriage 22 is supported for lateral movement .on a pair .of shafts 52, 54 which pass through and. slida'bly engage the side plates of the carriage 22, one of which is indicated at .53. A Windlass drum 56 extending between the side plates of the carriage 22 is supportedin the print hammer carriage by a splined shaft 58 journaled at the ends thereof in the side frames of the tabulating machine. The Windlass drum is rotated bythetsplined shaft, and it is moved laterally along the splined shaft by the side plate of the print hammer carnage.

Each print hammer is actuated by a ribbon which extendsaround the Windlass drum. The ribbon 60 for the print hammer 13 is shown in Fig. 4. The ribbon is secured to the carriage by a spring 62 so that the ribbon fits loosely around the drum. A spring 64 maintains the print hammer against the fixed stop 66 until it is actuated.

Ten solenoids 71 to 80 are provided for operating the print hammers 11 to 20, the solenoids 71 to 73 being shown on Fig. 4. The various solenoids are offset in order to allow them to be located in close proximity adjacent the Windlass drum. Each of these solenoids is provided with a roller 82 located on its armature. When a solenoid is energized, the roller or its armature engages the associated ribbon and causes it to be held firmly against the Windlass drum. The rotation of the windlass drum tends to carry the ribbon with it, thereby operating the print hammer to which the ribbon is attached. In this manner the print hammer is moved forwardly to actuate the type which is opposite it. The impact of the print hammer causes the character of the type to be printed on the paper by the inked ribbon.

A motor 84 is coupled to the splined shafts 3S and 58 by two belts 86 and 88. This motor causes the two splined shafts to rotate continuously while the machine is in operation. A commutator 99 is provided at the right-hand end of the splined shaft 38, with the rotor 92 of the commutator being coupled to the splined shaft so as to rotate with it. The commutator serves to control the operation of the print hammers so that they are actuated in synchronism with movement of the type belt, as will be explained with reference to Figs. 5, 6, and 7.

A paper advance solenoid 94 which operates a ratchet and pawl 96 serves to advance the paper through the machine after each line of copy has been printed.

The spacing between the print hammers is equal to the spacing between the characters on the type belt, and the type belt is moved along the print hammers at the rate of one character per segment traversed by the rotor of the commutator, so that the characters are located opposite the print hammers in accordance with the character position table of Fig. 5. By operating the print hammers at times which are determined by the desired characters and the locations at which the characters are to be recorded, any of the characters on the type belt may be printed at any desired location in the block during each print cycle.

By way of example, if the block of characters to be printed is +.95 103072, the print hammers strike as follows: v

Table [I Print Hammer Character Rotor on Commutator Segment Number Printed Actuated none none 19 none none none none none none none none 15 and 16 l and 0 none none 11 13 and 20 9 and z norli none If the block of characters to be printed were +987654321, all of the print hammers would strike simultaneously at the time when the commutator rotor is on segment L.

The diagram of Fig. 6 shows an electrical arrangement for controlling the print hammer solenoids and for controlling the lateral movement of the carriages.

A selector storage 98 is provided for selecting the print hammer solenoids which are energized when the commutator rotor engages each of the segments A to O. The selector storage comprises a set of ten selector switches 191 to 110. Each selector switch is provided with 13 contacts and a movable elector such as the selector 112 for the switch 01. Also, each switch is provided with an actuator 114 for moving the selector to the desired switch contact so as to select the character to be printed.

The selector arms of the selector switches are connected to the respective print hammer solenoids, and the digits to be printed by the respective print hammers are determined by the vertical position of the selector arm of the associated selector switches. The contacts of each selector switch are designated by the numerals 0 to 9 and the characters plus, minus, and period, with the bottom contact representing 0 and the uppermost contact representing the period.

Preferably the selector storage unit 98 is separated from the tabulator proper. Ordinarily the selector storage is the output circuit of a data processing device, and the tabulator serves to record the digital information produced at the output of the data processing device.

A start tab switch 116 and a pair of relays 118 and 120 control the operation of the tabulator during each print cycle.

A carriage position stepping switch 122 controls the operation of the carriage position servo so that the type and print hammer carriages are moved one step laterally after each print cycle. The carriage position stepping switch may be a rotary type stepping switch or it may be a telephone type stepping switch which automatically returns to its starting position after completing the required number of steps. The stepping switch serves to cause a pair of contacts 124 and 126 to move one step each time that the stepping switch is energized. The contact 124 serves to engage a plurality of taps along a resistance 128. The contact 126 serves to engage a contact which is connected to the paper advance solenoid, and it serves to energize this solenoid after one line of characters has been recorded so as to advance the paper one step.

A resistance 130 and a source of potential 132 are connected in shunt across the resistance 128. A servo amplifier 134 has its input circuit connected to the movable contact 124 and to a tap on the resistor 130 so that the servo amplifier causes the carriage position servomotor 46 to move the type and print hammer carriages laterally in accordance with the position of the contact 124 of the, stepping switch. An arrangement for providing ten lateral steps is illustrated; however, it will be apparent that any desired number of steps may be employed so long as the width of the paper is suflicient to accommodate the blocks of character: which are to be recorded along each line. If only one block of characters is to be recorded along each line, lateral movement of the type and print hammer carriages is unnecessary.

A source of potential 150 provides the current required to energize the windings of the relays 118, 120,

the paper advance solenoid 94, and the carriage position stepping switch 122.

In operation, the drive motor 84 is turned on so that the type belt and the commutator rotate continuously. The start tab switch is closed for the duration of each print cycle. Each print cycle is the cycle required for one complete block of characters to be recorded. In the present example it is the time required for the commutator to complete one revolution and cause ten characters to be printed. Closure of the start tab contacts applies ground to the rotor 92 of the commutator, when the rotor contacts segment A of the commutator, the winding of relay 118 is energized by the connection to ground through the contacts 136 of the relay 129 and the commutator segment A. The relay 118 locks to the start tab ground through the contacts 138 and 140.

The rotor of the commutator contacts each of the commutator segments A to O in sequence and this causes the print hammer solenoids to be energized through the selector storage switches and the contacts 142 of the relay 118 so as to cause the print hammers to actuate the selected type. The selector storage switches illustrated in Fig. 6 are set to cause the block of characters +.95103072 to be printed, and the print hammers strike in the sequence shown in Table I.

The print cycle is completed when the rotor of the commutator contacts the segment 0. This energizes the winding of the relay 129 by connecting it to ground through the contacts 144 of the relay 118. The winding of the relay 12.0 locks to the start tab ground through the contacts 146 so that the relay 129 is energized as long as the start tab switch remains closed. This prevents the print hammer solenoids from being energized until the start tab switch is opened so as to de-energize the relay 120 and then the print hammer solenoids may be energized again by closing the start tab switch contacts to initiate a new print cycle.

The carriage position stepping switch is energized at the end of each print cycle through the contacts 148 of the relay 120.

Thus, the selector storage switch contacts are set for the print cycle, and then the start tab switch is closed for a time long enough to allow the block of ten characters to be printed. Then the start tab switch is opened, the selector storage is set for the next print cycle and the start tab switch is closed again to cause the second block of characters to be printed, and so on.

The successive blocks of information are printed along a line on the paper until the line is completed, whereupon the carriage position stepping switch returns to its initial position and the paper advance solenoid causes the paper to move one step through the machine so that a new line can be recorded.

In order to simplify the present disclosure the start tab switch and the selector storage switches are illustrated as being mechanically actuated. It will be apparent that for high speed operation the switching arrangements may be electrically actuated and some provision can be made for automatically closing the start ta'b switch as soon as the selector storage switches have been set for each print cycle. The selector storage switches may be telephone type stepping switches, relay contacts, or mechanically operated switches, for example.

I claim:

1. A tabulator comprising an endless belt, a plurality of type aflixed to the belt in a predetermined sequence and representing characters to be recorded, a plurality of aligned hammers located opposite one side of the belt with the spacing between the hammers being approximately equal to the spacing of the type on the belt, a plurality of electromagnets for actuating the hammers, means for moving the belt at a predetermined speed, a commutator moving in synchronism with movement of the belt and having a plurality of segments including one for each type character on the belt, a plurality of selector switches, one selector switch being coupled to a corresponding one of the electromagnets and being arranged to connect the corresponding electromagnet to selected ones of the commutator segments for selectively operating any number of the hammers at predetermined times to actuate selected type at predetermined locations as the-respective type moves opposite the respective hammers.

2. A tabulator comprising an endless belt having two sequentially positioned sets of printing characters arranged along the belt, the characters in the two sets being in identical predetermined sequence, a printing medium positioned adjacent a portion of the belt, means for moving the belt with respect to the printing medium, a plurality of means for transferring images of the characters on the belt to the recording medium in response to an electrical impulse, commutating means operated in synchronism with said moving means, said commutating means having a plurality of output circuits which are successively energized by the commutating means in synchronism with the movement of the belt, the number of output circuits being equal to the number of characters in one set of characters on the belt, and a plurality of selector means equal in number to the number of character transferring means, each selector means being connected to a corresponding one of the character transferring means, each selector means further being arranged to selectively connect the corresponding transferring means to one of the output circuits of the commutating means for selectively actuating the transferring means in synchronism with the movement of the belt to transfer selected characters at predetermined locations on the recording medium as the respective characters move adjacent the respective character transferring means.

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